Contact tube



FIG. 1 shows a top, front and side perspective view of a contact tube, showing our new design;

FIG. 2 shows a side view thereof;

FIG. 3 shows a top view thereof;

FIG. 4 shows a bottom view thereof;

FIG. 5 shows an opposite side view thereof;

FIG. 6 shows a rear view thereof; and,

FIG. 7 shows a front view thereof.

The areas shown in broken lines depict unclaimed environmental subject matter and form no part of the claimed design. 

The ornamental design for a contact tube, as shown and described. 